BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES, GOODWILL AND INTANGIBLES (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2015 USD ($) Property	Oct. 31, 2014 USD ($)	Oct. 31, 2015 USD ($) Property	Oct. 31, 2014 USD ($) Property	Apr. 30, 2015 USD ($)
IDENTIFIED INTANGIBLE ASSETS AND LIABILITIES AND GOODWILL [Abstract]
New intangible assets			$ 1,300,000	$ 365,000
Addition to intangible liabilities			$ 101,000	$ 0
Weighted average lives of intangible assets and intangible liabilities			9 months 18 days	6 months
Identified intangible assets (included in intangible assets) [Abstract]
Gross carrying amount	$ 45,127,000		$ 45,127,000		$ 45,823,000
Accumulated amortization	(19,839,000)		(19,839,000)		(19,610,000)
Net carrying amount	25,288,000		25,288,000		26,213,000
Identified intangible liabilities (included in other liabilities) [Abstract]
Gross carrying amount	159,000		159,000		82,000
Accumulated amortization	(44,000)		(44,000)		(61,000)
Net carrying amount	115,000		115,000		21,000
Goodwill [Line Items]
Goodwill	$ 1,715,000		1,715,000		1,718,000
Goodwill impairment			0		0
Goodwill derecognized			193,000	$ 11,000	0
Goodwill recognized			$ 0	$ 852,000
Commercial Office [Member]
Reclassifications [Abstract]
Number of real estate properties classified as held for sale in discontinued operations | Property	48		48
Commercial Retail Properties [Member]
Goodwill [Line Items]
Number of real estate properties sold | Property			7
Reclassifications [Abstract]
Number of real estate properties classified as held for sale in discontinued operations | Property	17		17
Commercial Healthcare [Member]
Reclassifications [Abstract]
Number of real estate properties classified as held for sale in discontinued operations | Property	1		1
Multifamily [Member]
Goodwill [Line Items]
Number of real estate properties sold | Property				1
Acquired Below-Market Leases and Acquired Above-Market [Member]
Identified intangible liabilities (included in other liabilities) [Abstract]
Amortization of intangible assets	$ 4,000	$ 6,000	$ 11,000	$ 11,000
Estimated annual amortization [Abstract]
2017					3,000
2018					(11,000)
2019					(20,000)
2020					(16,000)
2021					(13,000)
Other Identified Intangible Assets [Member]
Identified intangible liabilities (included in other liabilities) [Abstract]
Amortization of intangible assets	1,200,000	$ 1,700,000	2,200,000	$ 2,900,000
Estimated annual amortization [Abstract]
2017					3,835,000
2018					3,605,000
2019					3,507,000
2020					3,440,000
2021					3,312,000
Held-for-Sale Properties [Member]
Goodwill [Line Items]
Goodwill	$ 3,000		$ 3,000		$ 193,000